1. Field of the Invention
This invention relates to an electro-luminescence display, and more particularly to an electro-luminescence display that is capable of being made having a small thickness and minimizing its length.
2. Description of the Related Art
An electro-luminescence display (ELD) is a display device taking advantage of an electro-luminescence (EL) phenomenon of generating a light by a voltage applied to a fluorescent material. Such an ELD is classified into an inorganic ELD and an organic ELD depending on its material and structure.
FIG. 1 shows a conventional inorganic ELD. Referring to FIG. 1, the inorganic ELD includes an upper insulating layer 34, a lower insulating layer 38, a luminescent layer 36 formed between the upper and lower insulating layers 34 and 38, and a transparent electrode 40 formed on the upper insulating layer 34, The transparent electrode 40 is arranged at the rear side of a glass substrate 41.
The upper and lower insulating layers 34 and 38 are made from a dielectric material. Thus, the upper and lower insulating layers 34 and 38 have desired capacitance values upon application of a voltage. The luminescent layer 36 is excited by electrons and is luminous, to thereby generate a visible light. The luminescent layer 36 is formed from a material such as ZnS or Mn, etc.
A rear electrode 32 is formed from a conductive material such as Al, etc. The rear electrode 32 receives a scanning pulse from a gate driving circuit (not shown) . The transparent electrode 40 is formed from a transparent conductive material such as indium-tin-oxide (ITO), etc, The transparent electrode 40 receives data from a data driving circuit (not shown). If a scanning pulse is applied to the rear electrode 32 and data is supplied to the transparent electrode 40, that is, if a voltage is applied between the rear electrode 32 and the transparent electrode 40, then holes are accelerated toward the rear electrode 32 while electrons are accelerated toward the transparent electrode 40. Such electrons and holes collide with each other at the center of the luminescent layer 36. The luminescent layer 36 generates a visible light when the electrons collide with the holes.
FIG. 2 shows a conventional organic ELD. Referring to FIG. 2, the organic ELD includes a metal electrode 42, a transparent electrode 48, a luminescent layer 45 formed between the metal electrode 42 and the transparent electrode 48, an electron transferring layer 43 and an electron carrying layer 44 formed between the luminescent layer 45 and the metal electrode 42, and a hole transferring layer 47 and a hole carrying layer 46.
The metal electrode 42 is made from a conductive material such as Al, etc. The metal electrode 42 receives a scanning pulse from a gate driving circuit (not shown). The transparent electrode 48 is formed from a transparent conductive material such as ITO, etc. The transparent electrode 48 receives data from a data driving circuit (not shown). If a scanning pulse is applied to the metal electrode 42 and data is supplied to the transparent electrode 48, then holes are accelerated toward the metal electrode 42 while electrons are accelerated toward the transparent electrode 48.
The electron-transferring layer 43 supplies electrons from the metal electrode 42 to the electron-carrying layer 44. The electron-carrying layer 44 accelerates the electrons from the electron-transferring layer 43 and supplies them to the luminescent layer 45. The hole transferring layer 47 supplies holes from the transparent electrode 48 to the hole-carrying layer 46. The hole-carrying layer 46 accelerates the hole from the hole-transferring layer 47 and supplies them to the luminescent layer 45.
The holes from the hole carrying layer 46 and the electrons from the electron-carrying layer 44 collide with each other at the center of the luminescent layer 45. The luminescent layer 45 generates a visible light when the electrons collide the holes.
In order to drive the inorganic ELD and the organic ELD, there is required a plurality of integrated circuits (IC's) for transferring a scanning pulse and a data supplied from the gate driving circuit and the data driving circuit. Such IC's is mounted by a chip on board (COB) system, a tape automated bonding (TAB) system or a chip on glass (COG) system. The TAB system is most widely used because it is possible to widen an effective area of a panel and the mounting process is simple. In the TAB system, the IC's are mounted onto a tape carrier package (TCP), which is connected among the gate driving circuit, the data driving circuit and an EL panel,
Referring to FIG. 3, a TCP of TAB system includes a base film 22 mounted with an IC 14, and input/output pads 24 and 26 connected to input/output pins of the IC 14. The input/output pads 24 and 26 have two-layer structures in which a copper (Cu) is plated with a tin (Sn) so as to prevent an oxidation. Such a TCP 12 is arranged between a first input pad of the EL panel 30 and a gate driving circuit 6 as shown in FIG. 4. Further, the TCP 12 is arranged between a second input pad of the EL panel 30 and a data driving circuit 7. The input pads 24 of the TCP 12 are connected to the gate driving circuit 6 and the data driving circuit 7. The output pads 26 of the TCP 12 are connected to the EL panel 30. The first and second pads of the EL panel 30 are provided at a non-display area of the EL panel.
As shown in FIG. 5, the TCP 12 is secured to the non-display area of the EL panel 30 so as not to cover an effective display area of the EL panel 30 emitting a visible light. In this case, since the TCP 12 is secured to the non-display area of the EL panel 30 in a folded shape, it has a desired thickness “a” as shown in FIG. 6. In other words, the thickness of the ELD is increased by said desired thickness “a”. In the mean time, since the driving circuits 6 and 7 should be secured to the non-display area of the EL panel 30, the IC 14 and the input pad 24 are formed to have a desired length “b”. If the IC 14 and the input pad 24 have said desired length “b”, then the ELD should be enlarged by the desired length “b” of the EL panel 30. In other words, it is difficult to make a conventional ELD having a small dimension due to the increase in thickness and length caused by the TCP 12.